Dialkyl acetals of heterocyclic ureidoacetaldehyde

ABSTRACT

WHEREIN R1 and R2 are each alkyl of up to three carbon atoms. Further described are herbicidal compositions utilizing the above defined compositions.   This invention discloses new chemical compounds of the formula

United States Patent 1 Krenzer Sept. 18, 1973 DIALKYL ACETALS OF HETEROCYCLIC UREIDOACETALDEHYDE [75] Inventor: John Krenzer, Oak Park, Ill.

[73] Assignee: Velsicol Chemical Corporation, Chicago, ll].

[22] Filed: Dec. 13, 1971 [2]] Appl. No.: 207,529

[52] U.S. Cl. 260/306.8 D, 71/90 [51] Int. Cl C07d 91/62 [58] Field of Search 260/306.8 D

Primary Examiner-Richard J. Gallagher Attorney-Robert J. Schwarz [57] ABSTRACT This invention discloses new chemical compounds of the formula 4 Claims, No Drawings DIALKYL ACETALS F HETEROCYCLIC UREIDOACETALDEHYDE This invention relates to new compositions of matter and more particularly relates to new chemical compounds of the formula wherein R and R are each alkyl of up to three carbon atoms.

The compounds of this invention are useful as herbicides and control a wide variety of weeds without significantly damaging beneficial plants such as corn or rice.

The compounds of this invention can be readily prepared from the isocyanate dimer of the formula by reaction with dialkyl acetal of the formula (III) wherein R and R are each alkyl of up to three carbon atoms. This reaction can be effected by heating a mixture of a molar amount of the isocyanate of formula II with about 2 molar amounts of the acetal of formula lll in an inert organic reaction medium such as benzene at the reflux temperature of the mixture. Heating at reflux can be continued for a period of from about 2 to about 30 minutes to ensure completion of the reaction. After this time the desired product can be recovered upon evaporation of the reaction medium and can be used as such or can be further purified by standard techniques in the art such as recrystallization and the like.

The compound of formula ll can be prepared by the procedure detailed in Example I. The preparation of the compounds of the present invention is more specifically illustrated in the following examples.

EXAMPLE 1 Preparation of 2-trifluoromethyl-l,3,4-thiadiazol-5-yl lsocyanate Dimer A saturated solution of phosgene in ethyl acetate 100 ml) was charged into a glass reaction vessel equipped with a mechanical stirrer. A slurry of 2- trifluoromethyl-S-amino-l,3,4-thiadiazole (45 grams) in ethyl acetate (300 ml) was added to the reaction vessel and the resulting mixture was stirred for a period of about 16 hours resulting in the formation of a precipitate. The reaction mixture was then purged with nitrogen gas to remove unreacted phosgene. The purged mixture was filtered to recover 48 grams of a white solid. This solid was recrystallized from dimethyl formamide to yield the desired product 2-trifluoromethyl- 1.3,4-thiadiazol-5-yl isocyanate dimer.

EXAMPLE 2 Preparation of the Dimethyl Acetal of 2-[3-(2- Trifluoro-methyll ,3 ,4-thiadiazol-5- yl)ureido]acetaldehyde A mixture of Z-trifluoromethyl-l,3,4-thiadiazol-5-yl isocyanate dimer (9.5 grams), the dimethyl acetal of 2- methylaminoacetaldehyde (5.8 grams) and benzene (60 ml) are charged into a glass reaction vessel equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux for a period of about 15 minutes. After this time the ,mixture is stripped of benzene under reduced pressure to yield a solid product as the residue. This product was recrystallized from heptane to yield the desired product the dimethyl acetal of 2-[3-( 2-trifluoromethyl-l,3,4- thiadiazol-S-yl)ureido]acetaldehyde having a melting point of 101 to 102C.

EXAMPLE 3 Preparation of the Diethyl Acetal of 2-[3-(2- trifluoromethyll ,3 ,4-thiadiazol-5- yl)ureido]acetaldehyde A mixture of 2-trifluoromethyl-1,3,4-thiadiazol-5-yl isocyanate dimer (6 grams), the diethyl acetal of 2- methylaminoacetaldehyde (4 grams) and benzene (50 ml) is charged into a glass reaction flask equipped with mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux, with stirring for a period of about 10 minutes. After this time the reaction mixture is'stripped of benzene to yield a solid product. This product is recrystallized from pentane to yield the desired product the diethyl acetal of 2-[3-(2- trifluoromethyll ,3 ,4-thiadiazol-5- yl)ureido]acetaldehyde.

EXAMPLE 4 Preparation of the Diisopropyl Acetal of 2-[3-(2- trifluoromethyl-l ,3,4-thiadiazol-5- yl)ureido]acetaldehyde A mixture of 2-trifluoromethyl-1,3,4-thiadiazol-5-yl isocyanate dimer (6 grams), the diisopropyl acetal of 2- methylaminoacetaldehyde (4.2 grams) and benzene (50 ml) is charged into a glass reaction flask equipped with a mechanical stirrer and reflux condenser. The reaction mixture is heated at reflux, with stirring for a period of about 10 minutes. After this time the reaction mixture is stipped of benzene to yield a solid product. This product is recrystallized from pentane to yield the desired product the diisopropyl acetal of 2-[3-(2- trifluoromethyl-l ,3 ,4-thiadiazol-5- yl)ureido]acetaldehyde.

For practical use as herbicides the compounds of this invention are generally incorporated into herbicidal compositions which comprise an inert carrier and a herbicidally toxic amount of such a compound. Such herbicidal compositions, which can also be called formulations, enable the active compound to be applied conveniently to the site of the weed infestation in any desired quantity. These compositions can be solids such as dusts, granules, or wettable powders; or they can be liquids such as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the active compound with a solid inert carrier such as the talcs, clays, silicas, pyrophyllite, and the like. Granular formulations can be prepared by impregnating the compound, usually dissolved in a suitable solvent, onto and into granulated carriers such as the attapulgites or the vermiculites, usually of a particle size range of from about 0.3 to 1.5 mm. Wettable powders, which can be dispersed in water or oil to any desired concentration of the active compound, can be prepared by incorporating wetting agents into concentrated dust compositions.

In some cases the active compounds are sufficiently soluble in common organic solvents such as kerosene or xylene so that they can be used directly as solutions in these solvents. Frequently, solutions of herbicides can be dispersed under superatmospheric pressure as aerosols. However, preferred liquid herbicidal compositions are emulsifiable concentrates, which comprise an active compound according to this invention and as the inert carrier, a solvent and an emulsifier. Such emulsifiable concentrates 'can be extended with water and or oil to any desired concentration of active compound for application as sprays to the site of the weed infestation. The emulsifiers most commonly used in these concentrates are nonionic or mixtures of nonionic with anionic surface-active agents. With the use of some emulsifier systems an inverted emulsion (water in oil) can be prepared for direct application to weed infestations.

A typical herbicidal composition according to this invention is illustrated by the following example, in which the quantities are in parts by weight.

EXAMPLE 5 Preparation of a Dust Product of Example 2 Powdered Talc 90 The above ingredients are mixed in a mechanical grinder-blender and are ground until a homogeneous, free-flowing dust of the desired particle size is obtained. This dust is suitable for direct application to the site of the weed infestation.

I The compounds of this invention can be applied as herbicides in any manner recognized by the art. One method for the control of weeds comprises contacting the locus of said weeds with a herbicidal composition comprising an inert carrier and as an essential active ingredient, in a quantity which is herbicidally toxic to said weeds, a compound of the present invention. The concentration of the new compounds of this invention in the herbicidal compositions will vary greatly with the type of formulation and the purpose for which it is designed, but generally the herbicidal compositions will comprise from about 0.05 to about 95 percent by weight of the active compounds of this invention. In a preferred embodiment of this invention, the herbicidal compositions will comprise from about 5 to about 75 percent by weight of the active compound. The compositions can also comprise such additional substances as other pesticides, such as insecticides, nematocides, fungicides, and the like; stabilizers, Spreaders, deactivators, adhesives, stickers, fertilizers, activators, synergists, and the like.

The compounds of the present invention are also useful when combined with other herbicides and/or defoli ants, dessicants, growth inhibitors, and the like in the herbicidal compositions heretofore described. These other materials can comprise from about 5 to about percent of the active ingredients in the herbicidal compositions. Use of combinations of these other herbicides and/or defoliants, dessicants, etc., with the compounds of the present invention provide herbicidal compositions which are more efi'ective in controlling weeds and often provide results unattainable with separate compositions of the individual herbicides. The other herbicides, defoliants, dessicants and plant growth inhibitors, with which the compounds of this invention can be used in the herbicidal compositions to control weeds, can include chlorophenoxy herbicides such as 2,4-D, 2,4,5-T, MCPA, MCPB, 4(2,4-DB), 2,4- DEB, 4-CPB, 4-CPA, 4-CPP, 2,4,5-TB, 2,4,5-TES, 3,4- DA, silvex and the like; carbamate herbicides such as lPC, CIPC, swep, barban, BCPC, CEPC, CPPC, and the like; thiocarbamate and dithiocarbamate herbicides such as CDEC, metham sodium, EPTC, diallate, PEBC, perbulate, vemolate and the like; substituted urea herbicides such as norea, siduron, dichloral urea, chloroxyron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron, monolinuron, neburon, buturon, trimeturon and the like; symmetrical triazine herbicides such as simazine, chlorazine, atraone, desmetryne, norazine, ipazine, prometryn, atrazine, trietazine, simetone, prometone, propazine, ametryne, and the like; chloroacetamide herbicides such as alpha-chloro- N,N-dimethylacetamide, CDEA, CDAA, alpha-chloro- N-isopropylacetamide, 2-chloro-N- isopropylacetanilide, 4-(chloroacetyl)morpholine, l- (chloroacetyl)piperidine, and the like; chlorinated aliphatic acid herbicides such as TCA, dalapon, 2,3- dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoic acid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA, dicamba, tricamba, amiben, fenac, PBA, 2-methoxy-3,6- dichlorophenylacetic acid, 3-methoxy-2,6- dichlorophenylacetic acid, 2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoic acid and the like; and such compounds as aminotriazole, maleic hydrazide, phenyl mercuric acetate, endothal, biuret, technical chlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, diquat, erbon, DNC, DNBP, dichlobenil, DPA, diphenamid, dipropalin, trifluralin, solan, dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein, benefin, bensulide, AMS, bromacil, 2-(3,4-dichlorophenyl)-4-methyl-1,2,4- oxadiazolidine-3,5-dione, bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone, di phenatril, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, lPX, isocil, potassium cynate, MAA, MAMA, MCPES, MCPP, Ml-l, molinate, NPA, OCH, paraquat, PCP, picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA, brominil, planavin, sodium tetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone, sindone B, propanil and the like.

Such herbicides can also be used in the methods and compositions of this invention in the form of their salts, esters, amides, and other derivatives whenever applicable to the particular parent compounds.

Weeds are undesirable plants growing where they are not wanted, having no economic value, and interfering with the production of cultivated crops, with the growing of ornamental plants, or with the welfare of livestock. Many types of weeds are known, including annuals such as pigweed, lambsquarters, foxtail, crabgrass,

wild mustard, field pennycress, ryegrass, goose-grass, chickweed, wild oats, velvet leaf, purselane, barnyard grass, smartweed, knotweed, cocklebur, wild buckwheat, kochia, medic, corn cockle, ragweed, sowthistle, coffee-weed, croton, cuphea, dodder, fumitory, groundsel, hemp nettle, knowel, spurge, spurry, emex, jungle rice, pondweed, dog fennel, carpetweed, morning glory, bedstraw, ducksalad and naiad; biennials such as wild carrot, matricaria, wild barley, campion, chamomile, burdock, mullein, roundleaved mallow, bull thistle, houndstongue, moth mullein, and purple star thistle; or perennials such as white cockle, perennial rye-grass, quackgrass, johnson grass, Canada thistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock, nutgrass, field chickweed, dandelion, campanula, field bindweed, Russian knapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail, ironweed, sesbania, bulrush, cattail and winter-cress.

Similarly, such weeds can be classified as broadleaf or grassy weeds. It is economically desirable to control the growth of such weeds without damaging beneficial plants or livestock.

The new compounds of this invention are particularly valuable for weed control because they are toxic to many species and groups of weeds while they are relatively non-toxic to many beneficial plants. The exact amount of compound required will depend on a variety of factors, including the hardiness of the particular weed species, weather, type of soil, method of application, the kind of beneficial plants in the same area, and the like. Thus, while the application of up to only about 1 or 2 ounces of active compound per acre may be sufficient for good control of a light infestation of weeds growing under adverse conditions, the application of pounds or more of active compound per acre may be required for good control of a dense infestation of hardy perennial weeds growing under favorable conditrons.

The herbicidal toxicity of the new compounds of this invention can be illustrated by many of the established testing techniques known to the art, such as preand post-emergence testing.

The herbicidal activity of the compounds of this invention was demonstrated by experiments carried out for the pre-emergence control of a variety of weeds. In these experiments small plastic greenhouse pots filled with dry soil were seeded with the various weed seeds. Twenty-four hours or less after seeding the pots were sprayed with water until the soil was wet and the test compounds formulated as aqueous emulsions of acetone solutions containing emulsifiers were sprayed at the indicated concentrations on the surface of the soil.

After spraying, the soil containers were placed in the greenhouse and provided with supplementary heat as required and daily or more frequent watering. The plants were maintained under these conditions for a period of from to 21 days, at which time the condition of the plants and the degree of injury to the plants was rated on a scale of from O to 10, as follows: 0 no injury, 1,2 =-slight injury, 3,4 moderate injury, 5,6= moderately severe injury, 7, 8,9= severe injury and 10 death. The effectiveness of these compounds is demonstrated by the data in Table I.

The herbicidal activity of the compounds of this invention was also demonstrated by experiments carried out for the post-emergence control of a variety of weeds. In these experiments the compounds to be tested were formulated as aqueous emulsions and sprayed at the indicated dosage on the foliage of the weeds that have attained a prescribed size. After spraying, the plants were placed in a greenhouse and watered daily or more frequently. Water was not applied to the foliage of the treated plants. The severity of the injury was determined 10 to 15 days after treatment and was rated on the scale of from 0 to 10 heretofore described. The effectiveness of these compounds is demonstrated by the data in Table II.

TABLE I Pre-emergence Herbicide Activity of the Product of Ex. 2

Injury Rating Rate in lbs/acre Weed 8 4 2 Barnyard Grass 10 I0 IO Crabgrass 9 9 6 Downy Brome l0 l0 7 Foxtail l0 l0 9 Johnson Grass 9 9 8 Wild Oats l0 l0 8 Coffee Weed l0 l0 l0 Curly Dock l0 l0 8 Velvet Leaf 9 9 9 Wild Mustard IO l0 10 TABLE II Post-emergence Herbicide Activity of the Product of Ex. 2

Injury Rating Rate in lbs/acre Weed 8 4 2 Barnyard Grass l0 9 8 Crabgrass 10 I0 9 Downy Brome IO 10 9 Foxtail l0 9 8 Johnson Grass l0 l0 10 Wild Oats l0 l0 8 Coffee Weed l0 l0 l0 Curly Dock l0 l0 7 Bindweed 9 9 5 Matricaria 1O l0 l0 Pigweed l0 l0 7 Velvet Leaf l0 l0 9 Wild Mustard I0 10 I0 I claim: 1. A compound of the formula R -O-OR H* N 1 q l JCF; f-I $133 A) H S wherein R and R are each alkyl of up to three carbon atoms.

2. The compound of claim 1, the dimethyl acetal of 2-[ 3-( 2-trifluoromethyl-l ,3 ,4-thiadiazol-5- yl)ureido]acetaldehyde.

3. The compound of claim 1, the diethyl acetal of 2- [3-( 2-trifluoromethyl-l ,3 ,4-thiadiazol-5 yl)ureido]acetaldehyde.

4. The compound of claim 1, the dipropyl acetal of 2-[3-( 2-trifluoromethyll ,3,4-thiadiazol-5- yl)ureido]acetaldehyde.

2% UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.759494Q Dated September 18 l 1973 Inventor( John .Krenzer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In each instance in I Column 2, lines 6 19,24, 37, 42 and, 54; and

Column 6, lines 57, 60 and 63 Signed and sealed this 21st day of May 197%.

(SEAL) Attest:

Attesting Officer Commissioner of Patents 

2. The compound of claim 1, the dimethyl acetal of 2-(3-(2-trifluoromethyl-1,3,4-thiadiazol-5-yl)ureido) acetaldehyde.
 3. The compound of claim 1, the diethyl acetal of 2-(3-(2-trifluoromethyl-1,3,4-thiadiazol-5-yl)ureido) acetaldehyde.
 4. The compound of claim 1, the dipropyl acetal of 2-(3-(2-trifluoromethyl-1,3,4-thiadiazol-5-yl)ureido) acetaldehyde. 